Vehicle bumpers are designed to provide protection against impact. The bumpers provide the ability to absorb impacts resulting from minor collisions. Bumpers offer protection to other vehicle components by dissipating the kinetic energy generated by an impact. Energy-absorbing crush zones are completely ineffective if they are physically bypassed; an extreme example of this occurs when the elevated platform of a tractor-trailer completely misses the front bumper of a passenger car, and first contact is with the glass windshield of the passenger compartment. Airbag deployment sensors typically do not trigger until contact with an obstruction, and it is important that front bumpers be the first parts of a vehicle to make contact in the event of a frontal collision, to leave sufficient time to inflate the protective cushions. The height and placement of bumpers may be legally specified, to ensure that when vehicles of different heights are in an accident, the smaller vehicle will not slide under the larger vehicle or other bad incidents happen as a result of misalignment. However, under certain conditions, such as during pre-collision braking, for example, the vehicle operation may change the height of the bumper. Therefore a need exists to provide vehicles with the ability to further ensure that any collision that occurs does so by contacting the bumper of the vehicle.